Dental tool.



Patented Apr. 24.1900. N. n. Folin.

DENTAL TUL.

(Application led Aug. 8, 1899.)

(N0 Model.)

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NELSON ROBERT FORD, OF NEV YORK, N. Y.

DENTAL TOOL.

SPECIFICATION forming part of Letters Patent No. 647,956, dated April24, 1900.

4'Application led August 8, 1899. Serial No. 726,511. (No model.)

To all whom tr/tay concern.-

Beit known that I, NELSON ROBERT FORD,

a subject of the Queen of Great Britain, re-l siding in the borough ofBrooklyn, inthe city of New York, in the county of Kings and State ofNew York, have invented a new and useful Dental Tool or Instrument ofPeculiar Construction, said invention being fully and clearly describedin the following specification.

The object of my invention is to construct and provide a dental tool orinstrument that may be quickly, easily, and readily adjusted forretaining or holding crowns, caps, or bands, &@., without slipping whilegrinding, filing, and polishing the same.

The invention comprises a stem or handle with a threaded neck or shank,a thumb-nut in screw-threaded engagement with the said neck, a pluralityof retaining springs or spring arms which are outwardly curved aroundthe said thumb-nut, and a fixed collar fitting upon the stem or handleand provided with grooves through which the retaining-springs pass, sothat the said springs are rigidly attached at their lower ends to thesaid handle. These springs or spring-arms are susceptible of adjustmentby the action of the thumb-nut upon them. The nut pushes them apart asit is screwed up or down upon the neck, and the natural elasticity ofthe springs or spring-arms causes them to return to their normalposition when the pressure of the nut is removed.

When it is desired to fit a crown, cap, or band upon the holder, theretaining springs or spring-arms are first adjusted to their normal orminimum expansion. The crown, cap, or band is then placed over or uponthe retaining-points of the springs or spring-arms, and these are thenadjusted or expanded, so that the retaining-points will rmly grip thecrown, cap, or band, and thereby prevent slipping.

The invention is illustrated by the accompanying drawings, similarletters being used for similar parts throughout the several views, inwhich- Figure l is a side elevation, partly in section, of the holder`with the retaining springs or spring-arms adjusted to about their normalor minimum expansion. Fig. 2 also shows a side elevation of the holder,having placed thereon a crown, the said crown being gripped by theretaining springs or springarms; and Fig. 3 illustrates a sectional viewof a modification of said holder.

A is a stem or handle, having one end thereof reduced in circumferenceto forni a neck B, upon which is cut a screw-thread c.

O is an adjusting-nut mounted upon and in screw-threaded engagement withthe thread a and which may be regulated at the will of the operator.

b is a flange or rim of the adjusting-nut O.

D is a collar itting upon the stem or handle A and provided with groovesc c. This collar is fastened to the said stem or handle A by anysuitable means.

E E are elastic retaining springs or springarms. These springs orspring-arms extend from and are fastened and held in position to thesaid stem or handle A through grooves c c in the collar D and are curvedoutwardly and then inwardly around the nut or set-screw C to points d d,whence they again extend slightly outwardly or nearly parallel to pointsg g, and thence are bent slightly outwardly to points h h.

The free extremities of the spring-arms may be finished in any mannersuitable for tting into and gripping tooth crowns, caps, bands, and thelike. I style these extremities retaining-points, but do not therebylimit myself to any special conformation thereof.

It may b e found desirable to have the springs or spring-arms E Eserrated on their outward surfaces between points d d and 7i h to aid inpreventing the slipping of the crowns, caps, or bands when tted uponthem.

It is not my intention to confine myself to the precise form of holdershown and described, as certain modifications might be made withoutdeparting from the spirit of the invention-21s, for instance, thesprings may be inserted in any suitable manner or their curvatureslightly varied. Another possible variation would be to have the nutmounted upon a screw-threaded neck which engages with a correspondingscrew-threaded aperture in the handle, as illustrated by Fig. 3.

IOO

pable of fitting into and gripping with their free extremities, toothcrowns, caps, bands or similar articles, and rigidly attached at theirother extremities to a suitable handle, and adjustable by means of adiskyertically movable Within their curvature, substantially asdescribed.

In testimony whereof I have signed this specification in the presence oftwo subscribing witnesses.

NELSON ROBERT FORD.

Vitnesses:

JAMES G. K. LEE, JOHN ToBIN.

